Regarding the existing technique for touch sensitive displays, it always needs to configure an exclusive conducting line for signal/data readout, i.e. the readout line, in the pixel of the display. With reference to FIG. 1, which is a diagram illustrating the pixel structure of a conventional touch display according to the prior art, the pixel 10′ is defined by a pair of data lines D1, D2 and a pair of gate lines SELECT1, SELECT2, where the respective data signal is transmitted through the data lines D1 and D2. The pixel 10′ includes a first transistor T1′ for display, whose gate terminal is electrically connected to the gate line SELECT1. The source terminal of the first transistor T1′ is electrically connected to the data line D1, and the drain terminal thereof is electrically connected to the common line COMMON1, which is provided with a biased voltage, through a capacitor Cst. The photo element, e.g. the Photo TFT, is configured for generating a photo signal, and the second transistor, Readout TFT, electrically connected thereto provides the control for reading out the photo signal. In this case, the second transistor Readout TFT is electrically connected to a readout line, Readout1, and is controlled to be switched on by a gate pulse provided by the gate line SELECT2, so that the photo signal could be transmitted through the readout line Readout1.
Please refer to FIG. 2, which is a diagram schematically showing the equivalent circuit for the pixel of a further conventional touch sensitive display as provided in US patent application No. 2003/0156087. The photo-sensitive structure therefor, i.e. a pixel structure, mainly includes a photo thin film transistor (Photo TFT) interconnected to a readout thin film transistor (Readout TFT) and a further capacitor which interconnects the common line to the transistors, and the circuit therefor is operated in the charge mode. The pixel 20′ defined by data lines D1, D2 and gate lines SELECT1, SELECT2 is addressed by applying a voltage to the gate line, SELECT1, which switches the transistors on and allows the charges from the data lines to flow. Also, the Readout TFT is controlled by a gate pulse applied on a previous gate line, SELECT2, so as to control the photo signal readout for the pixel 20′, and the capacitor Cst2 interconnecting the common line, COMMON1, to the transistors is configured for signal storage. With respect to such configuration, in order to transmit the generated photo signal to an external circuit for being processed, the pixel 20′, also needs a further conductive line therefor, i.e. the readout line Readout1, so as to exclusively transmit the photo signal to be read. The readout line Readout1 is electrically connected to an external amplifier, so that the transmitted photo signal would be amplified thereby and then output to a processor for subsequent data determination and process, whereby the data display and the input operation for such conventional touch sensitive display is performed.
Please refer to FIG. 3(a), which is a diagram schematically showing the equivalent circuit for the pixel of a further conventional touch sensitive display. In this case, the pixel 20′ is defined by a first and a second gate lines G1, G2, and a first and a second data lines D1, D2 intersecting to each other. Furthermore, a readout line Readout1 is disposed between the first and the second data lines D1, D2 and passing through the pixel 20′, while a common line COMMON1 is disposed between the first and the second gate lines G1, G2, for electrically connecting each data lines of the pixel 20′. Moreover, there are two main parts, i.e. a pixel element 201′ and a photo element 202′ formed therein. In more specifics, the pixel element 201′ includes a photo TFT 2011′ having a first gate electrode connected to the first gate line G1, a first drain electrode connected to the first data line D1, and a first source electrode connected to the common line COMMON1. The photo element 202′ includes a switch TFT 2021′ having a second gate electrode connected to the second gate line G2, a second drain electrode, and a second source electrode connected to the readout line Readout1. Furthermore, the photo element 202′ further includes a photo TFT 2022′ having a third gate electrode and a third drain electrode, both of which are connected to the common line COMMON1, and a third source electrode connected to the second drain electrode of the switch TFT 2021′.
The configuration of readout line results in a disadvantage for image display. Please refer to FIG. 3(b), which is a diagram schematically illustrating the configuration of readout line Readout1 in the pixel of the mentioned touch sensitive display according to the prior art. Since the additional readout line Readout1 is essential for the photo signal transmission in such a configuration, which occupies a specific portion of active area of the display, the aperture ratio of the pixel having such readout line Readout1 is thus different from that of other pixels, i.e. W1<W2, as shown in FIG. 3(b). Therefore, the mentioned touch sensitive display is relatively disadvantageous in a non-uniform lightness resulting from the difference of aperture ratio.
In addition, the configuration of such readout line also brings a test defect for the display easily and causes the loss in yield accordingly, which may result in a relatively high production cost and a relatively poor display property thereof.
In order to overcome the mentioned issues of the conventional touch sensitive display, so as to further improve the uniformity of lightness therefor, a novel method for driving the signal transmission and readout in a pixel thereof as well as the novel pixel structure corresponding thereto is provided.